Monday, May 4, 2009
5-17
The Potential of Agro-Industrial Residues for Production of Holocellulases from Filamentous Fungi
Félix Gonçalves de Siqueira1, Luís Roberto Batista2, Eliane Gonçalves de Siqueira1, and Edivaldo X. F. Filho1. (1) Cellular Biology, University of Brasília, Campus Universitário, Brasília, Brazil, (2) Food Science, Federal University of Lavras, Lavras, Lavras, Brazil
Thirty fungal species, including Aspergillus oryzae, Penicillium citrinum, Fusarium proliferatum and Paecilomyces lilacinum, were isolated from agro-industrial residues. They were screened for their ability to produce holocellulase when cultured in liquid state media containing sugar cane bagasse or other agro-industrial residue as the carbon source. For convenience, cultivation conditions (other than temperature) and enzyme assays were the same for all fungi, i.e., no attempt at optimization of individual was made. The objective of this exercise was to identify fungi and holocellulase (cellulase, hemicellulase and pectinase) activities of academic and as well as of potential commercial application. The pattern of holocellulase induction was influenced by the type of agro-industrial residue present in the medium. They were detected in different incubation periods. Holocellulase activities were very active in extracts of Aspergillus oryzae. Fractionation of the crude extracts on ultrafiltration, gel filtration and ion-exchange chromatography procedures showed enzyme multiplicity. Some enzyme preparations were more active and stable at determined pH and temperature ranges. While some of the results obtained fall into discernible and expected patterns, the overall picture is one of variety. Some fungi and growth substrates yielded promising results.